Railway spine cars have been used to carry freight containers and semitrailers. Spine cars generally have a platform formed by a center sill running longitudinally down its center line with a series of parallel crossbearers extending transversely of the sill. Because the spine car does not have a solid floor, the American Association of Railroads (AAR) requires restraints on spine cars sufficient to brace a failed container floor.
One response to AAR's requirement was to provide a set of parallel channels along the top of the center sill. This solution is far less than ideal however, because these channels interfere with semitrailer brake equipment and underslung refrigeration equipment. Another response to the AAR requirement was to provide outriggers on the cars and limit the use of these cars to container hauling only. Therefore, existing modifications to spine cars to provide a container floor restraint yielded structures that limit the application and usefulness of the spine cars.
Accordingly, it is desirable to construct a spine car with a structure that would provide a restraint to failed container floors as required by the AAR. In addition, when a semitrailer is mounted on the car, the container floor restraint must provide adequate clearance for trailer equipment. Because the weight of a railway car is at a premium, the container floor restraint structure must achieve its function while adding a minimal amount of weight to the weight of the car.